Effect of Systemic Hypertension With Versus Without Left Ventricular Hypertrophy on the Progression of Atrial Fibrillation (from the Euro Heart Survey).

Hypertension is a risk factor for both progression of atrial fibrillation (AF) and development of AF-related complications, that is major adverse cardiac and cerebrovascular events (MACCE). It is unknown whether left ventricular hypertrophy (LVH) as a consequence of hypertension is also a risk factor for both these end points. We aimed to assess this in low-risk AF patients, also assessing gender-related differences. We included 799 patients from the Euro Heart Survey with nonvalvular AF and a baseline echocardiogram. Patients with and without hypertension were included. End points after 1 year were occurrence of AF progression, that is paroxysmal AF becoming persistent and/or permanent AF, and MACCE. Echocardiographic LVH was present in 33% of 379 hypertensive patients. AF progression after 1 year occurred in 10.2% of 373 patients with rhythm follow-up. In hypertensive patients with LVH, AF progression occurred more frequently as compared with hypertensive patients without LVH (23.3% vs 8.8%, p = 0.011). In hypertensive AF patients, LVH was the most important multivariably adjusted determinant of AF progression on multivariable logistic regression (odds ratio 4.84, 95% confidence interval 1.70 to 13.78, p = 0.003). This effect was only seen in male patients (27.5% vs 5.8%, p = 0.002), while in female hypertensive patients, no differences were found in AF progression rates regarding the presence or absence of LVH (15.2% vs 15.0%, p = 0.999). No differences were seen in MACCE for hypertensive patients with and without LVH. In conclusion, in men with hypertension, LVH is associated with AF progression. This association seems to be absent in hypertensive women

Progression From Paroxysmal to Persistent Atrial Fibrillation. Clinical Correlates and Prognosis

Objectives: We investigated clinical correlates of atrial fibrillation (AF) progression and evaluated the prognosis of patients demonstrating AF progression in a large population. Background: Progression of paroxysmal AF to more sustained forms is frequently seen. However, not all patients will progress to persistent AF. Methods: We included 1,219 patients with paroxysmal AF who participated in the Euro Heart Survey on AF and had a known rhythm status at follow-up. Patients who experienced AF progression after 1 year of follow-up were identified. Results: Progression of AF occurred in 178 (15%) patients. Multivariate analysis showed that heart failure, age, previous transient ischemic attack or stroke, chronic obstructive pulmonary disease, and hypertension were the only independent predictors of AF progression. Using the regression coefficient as a benchmark, we calculated the HATCH score. Nearly 50% of the patients with a HATCH score >5 progressed to persistent AF compared with only 6% of the patients with a HATCH score of 0. During follow-up, patients with AF progression were more often admitted to the hospital and had more major adverse cardiovascular events. Conclusions: A substantial number of patients progress to sustained AF within 1 year. The clinical outcome of these patients regarding hospital admissions and major adverse cardiovascular events was worse compared with patients demonstrating no AF progression. Factors known to cause atrial structural remodeling (age and underlying heart disease) were independent predictors of AF progression. The HATCH score may help to identify patients who are likely to progress to sustained forms of AF in the near future. \ua9 2010 American College of Cardiology Foundation

Phytoplankton blooms in Black Sea and Mediterranean coastal ecosystems subjected to anthropogenic eutrophication: similarities and differences

The similarities and differences in phytoplankton response to anthropogenic nutrient enrichment were studied in coastal sites of the Western Black Sea and the Eastern Mediterranean (Aegean Sea). Although by physico-chemical parameters, two different environments have been compared, the two regions exhibited similar features: 14 common bloom species in the list of bloom producing algae, the highest rate of occurrence and variety of microalgae involved in summer, the highest average level of competitors-strategies species during the summer outbursts, the similar range of maximum bloom densities attained, and similar capacity to sustain critical biomass during all seasons. The low taxonomic similarity (Bray-Curtis index lower than 30%) between the different basins and among sites, could be attributed to both natural factors and dissimilarities and to the gradients in nutrient levels and their ratios, as affected by the different nature and severity of the anthropogenic pressures on the coastal ecosystems. The results of the PCA analysis indicate that temperature and salinity are factors contributing to the differences outlined between the Aegean Sea and the Black Sea ecosystems, but the differences among the selected sites give support to the importance of nutrients and their ratios. Although competitive outcomes in phytoplankton species selection and succession cannot yet be predicted, the analysis suggests that anthropogenic nutrient enrichment could play an important role in driving the phytoplankton bloom performance. The comparative studies between different basins could be a step forward to highlight common patterns and modes of ecosystem response to anthropogenic eutrophication and to suggest common indices to scale eutrophication impact. Academic Pres

Seasonal horizontal and vertical variability in primary production and standing stocks of phytoplankton and zooplankton in the Cretan Sea and the Straits of the Cretan Arc (March 1994-January 1995)

Phytoplankton communities, production rates and chlorophyll levels, together with zooplankton communities and biomass, were studied in relation to the hydrological properties in the euphotic zone (upper 100 m) in the Cretan Sea and the Straits of the Cretan Arc. The data were collected during four seasonal cruises undertaken from March 1994 to January 1995. The area studied is characterised by low nutrient concentrations, low 14C fixation rates, and impoverished phytoplankton and zooplankton standing stocks. Seasonal fluctuations in phytoplankton densities, chlorophyll standing stock and phytoplankton production are significant; maxima occur in spring and winter and minima in summer and autumn. Zooplankton also shows a clear seasonal pattern, with highest abundances occurring in autumn-winter, and smallest populations in spring-summer. During summer and early autumn, the phytoplankton distribution is determined by the vertical structure of the water column. Concentrations of all nutrients are very low in the surface waters, but increase at the deep chlorophyll maximum (DCM) layer, which ranges in depth from about 75-100 m. Chlorophyll-a concentrations in the DCM vary from 0.22-0.49 mg m-3, whilst the surface values range from 0.03-0.06 mg m-3. Maxima of phytoplankton, in terms of cell populations, are also encountered at average depths of 50-75 m, and do not always coincide with chlorophyll maxima. Primary production peaks usually occur within the upper layers of the euphotic zone. There is a seasonal succession of phytoplankton and zooplankton species. Diatoms and 'others' (comprising mainly cryptophytes and rhodophytes) dominate in winter and spring and are replaced by dinoflagellates in summer and coccolithophores in autumn. Copepods always dominate the mesozooplankton assemblages, contributing approximately 70% of total mesozooplankton abundance, and chaetognaths are the second most abundant group. (C) 2000 Elsevier Science Ltd

Seasonal horizontal and vertical variability in primary production and standing stocks of phytoplankton and zooplankton in the Cretan Sea and the Straits of the Cretan Arc (March 1994-January 1995)

Phytoplankton communities, production rates and chlorophyll levels, together with zooplankton communities and biomass, were studied in relation to the hydrological properties in the euphotic zone (upper 100 m) in the Cretan Sea and the Straits of the Cretan Arc. The data were collected during four seasonal cruises undertaken from March 1994 to January 1995. The area studied is characterised by low nutrient concentrations, low 14C fixation rates, and impoverished phytoplankton and zooplankton standing stocks. Seasonal fluctuations in phytoplankton densities, chlorophyll standing stock and phytoplankton production are significant; maxima occur in spring and winter and minima in summer and autumn. Zooplankton also shows a clear seasonal pattern, with highest abundances occurring in autumn-winter, and smallest populations in spring-summer. During summer and early autumn, the phytoplankton distribution is determined by the vertical structure of the water column. Concentrations of all nutrients are very low in the surface waters, but increase at the deep chlorophyll maximum (DCM) layer, which ranges in depth from about 75-100 m. Chlorophyll-a concentrations in the DCM vary from 0.22-0.49 mg m-3, whilst the surface values range from 0.03-0.06 mg m-3. Maxima of phytoplankton, in terms of cell populations, are also encountered at average depths of 50-75 m, and do not always coincide with chlorophyll maxima. Primary production peaks usually occur within the upper layers of the euphotic zone. There is a seasonal succession of phytoplankton and zooplankton species. Diatoms and 'others' (comprising mainly cryptophytes and rhodophytes) dominate in winter and spring and are replaced by dinoflagellates in summer and coccolithophores in autumn. Copepods always dominate the mesozooplankton assemblages, contributing approximately 70% of total mesozooplankton abundance, and chaetognaths are the second most abundant group. (C) 2000 Elsevier Science Ltd

Microbial Food Web Structure and Its Impact on Primary Production in a Meso-Oligotrophic Coastal Area (Pagasitikos Gulf, Aegean Sea)

Seasonal structure and dynamics of the planktonic microbial food web (phytoplankton, bacteria, nanoflagellates and ciliates) were studied in the meso-oligotrophic Pagasitikos Gulf, NW Aegean Sea. Pagasitikos Gulf is exposed to anthropogenic activity and for this, the sampling covered different parts of the system (city of Volos, sewage effluents, central gulf, Trikeri channel, outer gulf). The standing stocks of all the microbial components fell within the range of other similar coastal systems. Depth integrated primary production (PP) indicated a spring phytoplankton bloom in April/May in all sampling sites. A second phytoplankton bloom was recorded in the western and the outer part of the gulf in the fall. An estimation of bacterial carbon demand indicated that in several cases the percentage of PP that is routed through heterotrophic bacteria is close or over 100%. This is consistent with the excess bacterial biomass relative to autotrophic biomass found in the system. Hence recycling processes mediated by heterotrophs and particularly bacteria are crucial for maintaining the structure and functioning of the planktonic community in Pagasitikos Gulf